There are a number of situations where it is desirable to monitor automatically one or more parameters. It is also desirable to enhance mobility and portability by efficiently utilizing battery-powered circuits, such as in electronic monitoring systems. One common situation is monitoring medical oxygen being inhaled by patients. Research shows that a number of patients in medical facilities have had medical issues caused by low oxygen or by running out of oxygen completely. The most common method of oxygen monitoring is performed using an analog pressure gauge mounted to an oxygen regulator that requires a medical professional to visually monitor the pressure in the oxygen tank by actual visual inspection of the pressure gauge.
Other forms of oxygen monitoring are currently available, including electronic versions that will monitor oxygen with a digital display representing the pressure in the oxygen tank. Many of these devices also have alarms to notify the user when the oxygen level is at a low level. These devices typically are battery operated and have no monitoring ability should the power level of the batteries become too low.
The lack of a backup capability in the event of power loss was seen as a deficiency by the Applicant. It would be desirable to have a pressure monitoring system that would remain functioning even if the battery was unable to power the electronics.